IN-LINE WITH OUR ANCESTORS - OCT-4 AND THE MAMMALIAN GERM

The transcription factor Oct-4 is expressed specifically in the totipo tent germline cycle of mice. Cells that lose Oct-4 differentiate along different paths to form embryonic and extraembryonic somatic tissue. Oct-4 may maintain the potency of stem and germline cells by preventin g all other differentiation pathways. Oct-4 may also regulate the mole cular differentiation of cells in the germ lineage as it progresses fr om the fertilized egg, through cleavage stage/morula blastomeres, blas tocyst, inner cell mass, epiblast, germ cells, and gametes. The factor s that regulate, and are regulated by, Oct-4 are reviewed with respect to the phenomena of cell potency and germ/soma segregation and differ entiation. BioEssays 20:722-732, 1998. (C) 1998 John Wiley & Sons, Inc .